Launch delays hamper near-term impact of GPS experimentation program

Yahoo

21-03-2025

The Space Force is looking for ways to experiment with new technologies on its next-generation GPS satellites, but persistent delays to a key demonstration program could limit its options.
The service planned to launch the Navigation Technology Satellite-3 demonstration, dubbed NTS-3, in 2022 with an eye toward experimenting with new positioning, navigation and timing signals and payloads that could be installed on future GPS satellites and shape its long-term plans for the constellation.
The satellite's development, led by the Air Force Research Lab and L3Harris, has proceeded on schedule, but delays to the rocket assigned to fly the spacecraft — United Launch Alliance's new Vulcan Centaur — have stalled the program for years. The mission is slated to fly on Vulcan's first national security launch this year, but those plans are on hold as the company awaits final certification from the Space Force.
Cordell DeLaPena, who oversees the Space Systems Center's positioning, navigation and timing and satellite communications portfolios, said the service is weighing its options for how to proceed with integrating NTS-3 technology into upcoming GPS production lines.
'The longer it takes to actually launch those experiments, get the data and be able to assess it, the window starts to close on the availability of production vehicles,' he told Defense News in an interview.
The Space Force had intended to funnel NTS-3-proven capabilities into the production line for its latest variant of GPS satellites, dubbed GPS IIIF. The service plans to buy 20 of these satellites from Lockheed Martin and, to date, has ordered 10. The first five of those spacecraft are slated for deliveries over a five-year period beginning in 2027.
ULA's new rocket won't fly its first Space Force missions until 2025
DeLaPena said GPS IIIF is approaching the end of its design period and will soon shift toward production. There's still room on the satellite for additional size, weight and power — or SWAP — which means the program could still make changes to incorporate NTS-3 technology. But the clock is ticking, he said.
'If there are a handful of these experiments that launch and prove themselves out on orbit and if they're mature enough to start considering maturing those concepts for production, that would be the path,' DeLaPena said.
If the the Space Force misses its window to install NTS-3 technology on the first five GPS IIIF satellites, the service could aim to include any relevant technology either on its next batch of five spacecraft or as part of other PNT programs, DeLaPena said. That includes a program called Resilient GPS, which is meant to augment the larger constellation with a fleet of small, lightweight, lower-cost satellites.
The Space Force's NTS-3 demonstration and its plans for Resilient GPS, or R-GPS, are part of a broader rethinking of its approach to providing navigation and timing capabilities. One piece of that involves the orbit in which satellites reside.
The military has traditionally launched its GPS satellites to medium Earth orbit, and that's where R-GPS will operate. However, the service is considering a multi-orbit approach for its future PNT capabilities. Along those lines, NTS-3 is destined for geosynchronous orbit, and the Space Development Agency plans to launch PNT satellites to low Earth orbit as part of its Proliferated Warfighter Space Architecture.
DeLaPena noted that demonstrating a 'blended,' multi-orbit navigation capability is a primary goal for NTS-3, adding that countries like Japan, South Korea and India are all exploring GEO-based systems.
The Space Force is in the midst of an analysis of alternatives that will further define a roadmap for the service's future mix of PNT capabilities. The need for an R-GPS capability was an outgrowth of that study, which should be completed this summer, DeLaPena said.